Japanese_Shift_Space

{
  "title": "Japanese",
  "rules": [
    {
      "description": "Shift + Space to next input method",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "spacebar",
            "modifiers": {
              "mandatory": [
                "shift"
              ]
            }
          },
          "to": [
            {
              "key_code": "open_bracket",
              "modifiers": [
                "option"
              ]
            }
          ]
        }
      ]
    }
  ]
}

$ touch ~/.config/karabiner/assets/complex_modifications/spacejap.json
$ vi ~/.config/karabiner/assets/complex_modifications/spacejap.json

# tab75
# reset all
$ left alt + right alt

# bluetooth
$ pn + left alt 3 sec
$ pn + j

# win bind
$ pn + q

# switch layer 1
$ pn + m

# switch fn
$ fn + left shift 3 sec